Chapter 13. Memory, Learning, and Development
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By Christie Aschwanden, A lawyer contacted Beatrice Golomb, a physician at the VA San Diego Healthcare Center, because he could no longer follow a normal conversation with his clients. A radiologist told Golomb that he found himself suddenly unable to distinguish left from right. A third person told her he had grown so forgetful that his doctor assumed he had Alzheimer’s. All three had developed their memory problems after taking a cholesterol-lowering statin drug, and the symptoms improved after they stopped the medication. The statin revolution began in 1987, when lovastatin was approved by the Food and Drug Administration. Since then, this class of drugs has transformed cardiac medicine, says Allen Taylor, chief of cardiology at MedStar Georgetown University Hospital. “Cardiovascular disease affects one in two people. This is the one drug that works.” But these drugs are not without risks. Golomb has amassed thousands of reports at her Web site Statineffects.com, detailing adverse reactions from statins. She says that cognitive problems are the second-most-common side effect reported in her database, after muscle pain. In a 2009 report in the journal Pharmacotherapy, Golomb described 171 patients who’d reported cognitive problems after taking statins. The idea that a cholesterol-lowering drug could make your brain fuzzy might sound crazy, and Golomb says the notion was greeted with suspicion at first. But eventually the FDA received enough such reports that last February it ordered drug companies to add a new warning label about possible memory problems. © 1996-2013 The Washington Post
Keyword: Learning & Memory
Link ID: 17905 - Posted: 03.15.2013
By GINA KOLATA The Food and Drug Administration plans to loosen the rules for approving new treatments for Alzheimer’s disease. Drugs in clinical trial would qualify for approval if people at very early stages of the disease subtly improved their performance on memory or reasoning tests, even before they developed any obvious impairments. Companies would not have to show that the drugs improved daily, real-world functioning. For more than a decade, the only way to get Alzheimer’s drugs to market was with studies showing that they improved the ability of patients not only to think and remember, but also to function day to day at activities like feeding, dressing or bathing themselves. The proposal, published online Wednesday in The New England Journal of Medicine, could help millions of people at risk of developing the disease by speeding the development and approval of drugs that might slow or prevent it. The proposed policy could also be a boon for the pharmaceutical industry and researchers. They have often felt stymied by regulations that left them uncertain of how to get drugs tested and approved for marketing to people early in the course of Alzheimer’s, when the medications are most likely to be useful. Several studies are being planned for people at high risk of developing Alzheimer’s, and the proposed regulations should lead to even more clinical trials, said Dr. P. Murali Doraiswamy, an Alzheimer’s researcher and professor of psychiatry at Duke University School of Medicine. © 2013 The New York Times Company
Link ID: 17904 - Posted: 03.15.2013
By Jan Brogan Paula Driscoll had a hard time sitting still as a kid, doodled a lot, and often wrestled with the feeling that she should be accomplishing more. But she made it through high school and college and became an elementary school teacher. With three small children at home, she did not feel she had trouble managing her life. But when her youngest child went to school, she found herself with what felt like too much time on her hands. “I couldn’t get anything done,” she said. “I had one room I started to paint, another I was going to reorganize, and I could never complete a task. I couldn’t stay in the house. I went out on one errand after the next.” Driscoll was 45 when she was diagnosed with attention deficit hyperactivity disorder, or ADHD. ADHD, a neurobiological disorder that makes it difficult to focus and can also include hyperactivity and impulsivity, has historically been viewed as a childhood disease. Over the last couple decades, research has shown that many of those afflicted carry symptoms into adulthood. The latest study, led by a Boston Children’s Hospital researcher and published Monday in the journal Pediatrics, suggests that nearly 30 percent of those with childhood ADHD still have the condition as adults — often after discontinuing treatment. The researchers followed hundreds of children with ADHD into adulthood and reported that the majority had mental health problems such as alcohol or drug dependence, anxiety, depression, or a personality disorder. © 2012 NY Times Co.
British researchers have developed a test to detect Alzheimer's disease in its earliest stages. It works by looking for a combination of "markers" in the blood which are different in healthy people and those with the disease. Delegates at the Alzheimer's Research UK Conference heard that the University of Nottingham is now developing a quick and easy test to do in clinics. It could mean much earlier diagnosis and better treatments, they said. The test uses some proteins that have been strongly linked with Alzheimer's disease, such as amyloid and APOE. But through careful analysis of blood from people with the disease, as well as those with early-stage memory problems, the researchers detected some other markers that were suggestive of the disease. Most notably, some proteins related to inflammation seem to have been added to increase the power of the test. Prof Kevin Morgan from the University of Nottingham said they still had to validate the test and it could be a decade before it was used in patients. But he added that the combination of markers they had found was looking very promising. BBC © 2013
Link ID: 17889 - Posted: 03.11.2013
by Moheb Costandi Mice transplanted with a once-discounted class of human brain cells have better memories and learning abilities than normal counterparts, according to a new study. Far from a way to engineer smarter rodents, the work suggests that human brain evolution involved a major upgrade to cells called astrocytes. Astrocytes are one of several types of glia, the other cells found alongside neurons in the nervous system. Although long thought to merely provide support and nourishment for neurons, it's now clear that astrocytes are vital for proper brain function. They are produced during development from stem cells called glial progenitors. In 2009, Steven Goldman of the University of Rochester Medical Center in New York and his colleagues reported that human astrocytes are bigger, and have about 10 times as many fingerlike projections that contact other brain cells and blood vessels, than those of mice. To further investigate these differences, they have more recently grafted fluorescently labeled human glial progenitors into the brains of newborn mice and examined the animals when they reached adulthood. Most of the grafted cells remained as progenitors, but some matured into typical human-looking astrocytes. They connected to their mouse counterparts to form astrocyte networks that transmitted electrical signals. Furthermore, they propagated internal signals about three times faster than the mouse astrocytes and improved the strengthening of connections between neurons in the hippocampus, a process thought to be critical for learning and memory. © 2010 American Association for the Advancement of Science.
By Deborah Kotz, Globe Staff No doubt, the biggest appeal of exercise is to build biceps, heart muscle, and perhaps some definition in those abdominal muscles, but how about using exercise to build your brain? It’s been known for some time that exercise can lift your mood, ward off depression, and help the brain age more gracefully -- free of memory loss and dementia. But now researchers have found that even just one bout of exercise can -- even better than a cup of coffee -- improve your mental focus and cognitive performance for any challenging task you face that day. A new analysis of 19 studies involving 586 kids, teens, and young adults that was published Wednesday in the British Medical Journal found that short 10 to 40 minutes bursts of exercise led to an immediate boost in concentration and mental focus, likely by improving blood flow to the brain. “These results provide further evidence that doing about 20 minutes of exercise just before taking a test or giving a speech can improve performance,” said Harvard psychiatrist Dr. John Ratey, who wrote the best-selling book Spark: The Revolutionary New Science of Exercise and the Brain. Another piece of proof can be seen in the brain scan above -- from a 2009 University of Illinois study also included in the new analysis -- which compares the brain activity of 9-year-olds who took a brisk walk and those who didn’t take a walk. The walkers had far more activity in brain regions involved with focused attention and filtering out noisy distractions while they were taking a challenging test compared to the non-walkers. © 2013 NY Times Co.
Keyword: Learning & Memory
Link ID: 17881 - Posted: 03.09.2013
by Andy Coghlan Stimulating the brain with electrical signals can sharpen some of your faculties, but now it seems it can dim others at the same time. Transcranial electrical stimulation (TES), delivered by electrodes on the surface of the head, has been shown to double people's speed of learning. Now the first evidence has emerged that improvements in one aspect of learning might come at the expense of other abilities. Roi Cohen Kadosh of the University of Oxford, showed volunteers pairs of unfamiliar symbols. Each symbol had a secret numerical value, and the volunteers' task was to state – as quickly as possible while avoiding mistakes – which symbol in a pair had the bigger value. The correct answer was then displayed. Over six sessions in one week, it was possible to measure how quickly and efficiently the volunteers learned the value of each symbol. Second task In a second task, participants had to register which of each pair of symbols was physically larger, a measure of automatic thinking. "Automaticity is the skill of doing things without thinking about them, such as reading, driving or mounting stairs," says Cohen Kadosh, who conducted the experiment with Teresa Iucalano of the Stanford Cognitive and Systems Neuroscience Laboratory in Palo Alto, California. During the experiments, volunteers received TES to their posterior parietal cortex – vital for numerical learning – or their dorsolateral prefrontal cortex – vital for automaticity. Some unknowingly received a sham treatment. © Copyright Reed Business Information Ltd.
Keyword: Learning & Memory
Link ID: 17877 - Posted: 03.09.2013
By GINA KOLATA The psychiatric illnesses seem very different — schizophrenia, bipolar disorder, autism, major depression and attention deficit hyperactivity disorder. Yet they share several genetic glitches that can nudge the brain along a path to mental illness, researchers report. Which disease, if any, develops is thought to depend on other genetic or environmental factors. Their study, published online Wednesday in the Lancet, was based on an examination of genetic data from more than 60,000 people worldwide. Its authors say it is the largest genetic study yet of psychiatric disorders. The findings strengthen an emerging view of mental illness that aims to make diagnoses based on the genetic aberrations underlying diseases instead of on the disease symptoms. Two of the aberrations discovered in the new study were in genes used in a major signaling system in the brain, giving clues to processes that might go awry and suggestions of how to treat the diseases. “What we identified here is probably just the tip of an iceberg,” said Dr. Jordan Smoller, lead author of the paper and a professor of psychiatry at Harvard Medical School and Massachusetts General Hospital. “As these studies grow we expect to find additional genes that might overlap.” The new study does not mean that the genetics of psychiatric disorders are simple. Researchers say there seem to be hundreds of genes involved and the gene variations discovered in the new study confer only a small risk of psychiatric disease. Steven McCarroll, director of genetics for the Stanley Center for Psychiatric Research at the Broad Institute of Harvard and M.I.T., said it was significant that the researchers had found common genetic factors that pointed to a specific signaling system. © 2013 The New York Times Company
Daphne Bavelier & Richard J. Davidson Video games are associated with a variety of negative outcomes, such as obesity, aggressiveness, antisocial behaviour and, in extreme cases, addiction2. At the same time, evidence is mounting that playing games can have beneficial effects on the brain. After spending an hour a day, 5 days a week for 8–10 weeks spotting snipers and evading opponents in shooter games such as Call of Duty or Unreal Tournament, young adults saw more small visual details in the middle of clutter and more accurately distinguished between various shades of grey3. After 10 hours stretched over 2 weeks spent chasing bad guys in mazes and labyrinths, players were better able to rotate an image mentally4, an improvement that was still present six months later and could be useful for activities as varied as navigation, research chemistry and architectural design. After guiding small rodents to a safe exit amid obstacles during a version of the game Lemmings that was designed to encourage positive behaviour, players were more likely in simulated scenarios to help another person after a mishap or to intervene when someone was being harassed5. Because gaming is clearly here to stay, some scientists are asking how to channel people's love of screen time towards positive effects on the brain and behaviour by designing video games specifically intended to train particular aspects of behaviour and brain function. One game, for example, aims to treat depression by introducing cognitive behavioural therapy while users fight off negative thoughts in a fantasy world6. In Re-mission, young cancer patients blast cancer cells and fight infections and the side effects of therapy — all to encourage them to stick with treatment (see www.re-mission.net). © 2013 Nature Publishing Group
Keyword: Learning & Memory
Link ID: 17859 - Posted: 03.02.2013
By Bruce Bower Children with dyslexia may read better after playing action video games that stress mayhem, not literacy, a contested study suggests. Playing fast-paced Wii video games for 12 hours over two weeks markedly increased the reading speed of 7- to 13-year-old kids with dyslexia, with no loss of reading accuracy, says a team led by psychologist Andrea Facoetti of the University of Padua, Italy. Reading gains lasted at least two months after the video game sessions. The gains matched or exceeded previously reported effects of reading-focused programs for dyslexia, the researchers report online February 28 in Current Biology. “These results are clear enough to say that action video games are able to improve reading abilities in children with dyslexia,” Facoetti says. Although the new study includes only 20 children with dyslexia, its results build on earlier evidence that many poor readers have difficulty focusing on items within arrays, Facoetti holds. By strengthening the ability to monitor central and peripheral objects in chaotic scenes, he says, action video games give kids with dyslexia a badly needed tool for tracking successive letters in written words. But evidence for Facoetti’s conclusions is shaky, asserts psychologist Nicola Brunswick of Middlesex University in London. The researchers tested word reading ability two months later but failed to test reading comprehension, she says. What’s more, they did so with a mere six of 10 kids who played the action video games. © Society for Science & the Public 2000 - 2013
Regina Nuzzo Despite having brains that are still largely under construction, babies born up to three months before full term can already distinguish between spoken syllables in much the same way that adults do, an imaging study has shown1. Full-term babies — those born after 37 weeks' gestation — display remarkable linguistic sophistication soon after they are born: they recognize their mother’s voice2, can tell apart two languages they’d heard before birth3 and remember short stories read to them while in the womb4. But exactly how these speech-processing abilities develop has been a point of contention. “The question is: what is innate, and what is due to learning immediately after birth?” asks neuroscientist Fabrice Wallois of the University of Picardy Jules Verne in Amiens, France. To answer that, Wallois and his team needed to peek at neural processes already taking place before birth. It is tough to study fetuses, however, so they turned to their same-age peers: babies born 2–3 months premature. At that point, neurons are still migrating to their final destinations; the first connections between upper brain areas are snapping into place; and links have just been forged between the inner ear and cortex. To test these neural pathways, the researchers played soft voices to premature babies while they were asleep in their incubators a few days after birth, then monitored their brain activity using a non-invasive optical imaging technique called functional near-infrared spectroscopy. They were looking for the tell-tale signals of surprise that brains display — for example, when they suddenly hear male and female voices intermingled after hearing a long run of simply female voices. © 2013 Nature Publishing Group
By Meghan Rosen Mouse brain cells scamper close to eternal life: They can actually outlive their bodies. Mouse neurons transplanted into rat brains lived as long as the rats did, surviving twice as long as the mouse’s average life span, researchers report online February 25 in the Proceedings of the National Academy of Sciences. The findings suggest that long lives might not mean deteriorating brains. “This could absolutely be true in other mammals — humans too,” says study author Lorenzo Magrassi, a neurosurgeon at the University of Pavia in Italy. The findings are “very promising,” says Carmela Abraham, a neuroscientist at Boston University. “The question is: Can neurons live longer if we prolong our life span?” Magrassi’s experiment, she says, suggests the answer is yes. One theory about aging, Magrassi says, is that every species has a genetically determined life span and that all the cells in the body wear out and die at roughly the same time. For the neurons his team studied, he says, “We have shown that this simple idea is certainly not true.” Magrassi’s team surgically transplanted neurons from embryonic mice with an average life span of 18 months into rats. To do so, the researchers slipped a glass microneedle through the abdomens of anesthetized pregnant mice. Then, using a dissecting microscope and a tool to illuminate the corn-kernel-sized mouse embryos, the researchers scraped out tiny bits of brain tissue and injected the neurons into fetal rat brains. After the rat pups were born, Magrassi and colleagues waited as long as three years, until the animals were near death, to euthanize the rats and dissect their brains. © Society for Science & the Public 2000 - 2013
By Janet Raloff Hospitals rush newborns into a neonatal intensive care unit when those babies are struggling to survive. Although NICUs offer tender and vigilant care, many of the devices they rely on can expose their tiny patients to a relatively large dose of a hormone-mimicking pollutant, bisphenol A. Newborns in intensive care excrete BPA, on average, at levels of around 17.8 micrograms per liter — well above the 0.45 µg/l typical of healthy infants, researchers report in the March Pediatrics. One of the most reliable indicators of BPA exposure was the level of care that a baby received, reflected by the number of devices used to deliver that care, notes nurse and exposure-science researcher Susan Duty of Simmons College in Boston. Breathing tubes, intravenous drug delivery lines and enclosed incubators are plastic, and several types of plastic can contain BPA. Although researchers have not figured out what doses of BPA cause toxicity in people, several studies have linked elevated prenatal exposures to later behavioral problems (SN Online: 7/16/12) and moodiness (SN: 11/7/09, p. 12) in young children. Animal studies have also linked BPA exposure during development to feminization in males and risks of later hypertension and diabetes. Duty’s team studied 55 infants, each of whom spent at least three days in a NICU in the Boston area, and most of whom had been born prematurely or were for other reasons very small. The researchers measured BPA in the breast milk and formula that these tiny babies consumed. Both nutritional sources had small, comparable amounts of BPA. © Society for Science & the Public 2000 - 2013
Sandrine Ceurstemont, editor, New Scientist TV It's the sequel to fertilisation: the brains of unborn babies have now been imaged in action, showing how connections form. This fMRI movie, produced by Moriah Thomason from Wayne State University in Detroit, Michigan, shows a fly-through of several fetuses in their third trimester. By comparing the scans at slightly different stages of development, Thomason was able to pinpoint when different parts of the brain wire up. "The connection strength increases with fetal age," writes Thomason. By identifying how brain connectivity normally develops, the scans could help diagnose and treat conditions like schizophrenia and autism before birth. For more on this research, read our full-length news story, "First snaps made of fetal brains wiring themselves up". © Copyright Reed Business Information Ltd.
Canadian researchers have found out how to restore normal vision to kittens with a lazy eye without using an eye patch. The cure was relatively simple — putting the kittens in complete darkness for 10 days. Once the kittens were returned to daylight, they regained normal vision in the lazy eye within a week, reported researchers at Dalhousie University in Halifax in the journal Current Biology this month. Lazy eye is a condition where the brain effectively turns off one eye. It affects about four per cent of the population in humans, and the most common treatment is fix the vision problem (for example, by using glasses) and then patch the good eye, forcing the person to use their bad eye. Kevin Duffy, a neuroscientist who co-authored the new study, told CBC's Quirks & Quarks that the condition is typically the result of a vision problem such as a cataract, a misalignment of the eyes, or poor focus in one eye, which then causes the brain to develop abnormally. "If the eye is providing abnormal vision, then the circuits that connect to that eye are going to develop abnormally," he said. The brain "becomes effectively disconnected." © CBC 2013
Stephen S. Hall Male sexual dysfunction is never pretty, even in nematodes. In normal roundworm courtship, a slender male will sidle up to a plump hermaphrodite, make contact, and then initiate a set of steps leading up to insemination: a sinuous backwards motion as he searches for the sexual cleft, a pause to probe, and finally the transfer of sperm. The whole business is usually over in a couple of minutes. “It's very slithery, and affectionate,” says Cornelia Bargmann, who has been observing the behaviour of this particular worm, Caenorhabditis elegans, for 25 years. Last October, scientists in Bargmann's laboratory at the Rockefeller University, New York, reported the discovery of a gene that seems to be crucial to successful mating. Disrupting the action of this gene causes male sexual confusion of almost epic pathos: nematodes with certain mutations poke tentatively at an inert hermaphrodite, making confused, fruitless curlicues around the potential mate. Occasionally the mutant male succeeds, but often he literally falls off the job and begins the search anew for a mate. Jennifer Garrison, a postdoc of Bargmann's who tracked the behaviour of these males, just shakes her head as she replays the scene on her computer screen. “Really sad,” she says. There are two punchlines to this story of thwarted invertebrate mating. One is the charming squeamishness with which Bargmann describes it, hesitating at words such as “vulva” and “spicule” and other anatomical gewgaws of roundworm reproduction. “As a well-brought-up Southern girl,” she says with a laugh, “it's still difficult to talk about this!” © 2013 Nature Publishing Group
By Steven Ross Pomeroy Everyone enjoys the occasional practical joke – assuming the gag isn’t mean-spirited or overly perilous, even the prank’s poor victim can appreciate the punch line! I’m sure you have your favorites: gluing dollars to sidewalks, filling your co-worker’s office with balloons, moving your roommate’s bed to the basement… while he’s sleeping in it. More typical stunts may employ whoopee cushions, fake vomit, and hand buzzers, but honestly, those are a tad sophomoric and overdone. Thus, in an effort to elevate the standard of stunts, I’d like to present a gag that makes use not of stink bombs, but of science. How to implant false memories in your friends, in four steps: In The Demon-Haunted World, Carl Sagan argued that implanting false memories in people is not only possible, but is actually pretty easy when attempted in the proper settings with a gullible subject, He cited as examples people who, at the urging of therapists or hypnotists, genuinely start to believe that they’d been abducted by UFOs or falsely remember being abused as a child. For these people, the distinction between memory and imagination becomes blurred, and events that never actually took place become sewn into their memories as real events. They can even describe these false remembrances incredibly vividly – as if they actually happened! “Memory can be contaminated,” Sagan wrote. “False memories can be implanted even in minds that do not consider themselves vulnerable and uncritical.” © 2013 Scientific American
Keyword: Learning & Memory
Link ID: 17827 - Posted: 02.20.2013
By Hristio Boytchev, Believing that brains can be trained through the use of specialized computer programs, researchers are focusing on helping people with schizophrenia, which can cause them to hear imagined voices or believe that others are controlling or plotting against them. There are medications for the often-disabling disorder, but they have severe side effects and don’t get rid of all symptoms; many people will not stick with the drugs. A California company, Posit Science, is developing a computer game that it hopes will become the first to earn approval from the Food and Drug Administration for treating schizophrenia. The idea comes from Michael Merzenich, an emeritus professor of neuroscience at the University of California at San Francisco and a co-founder of Posit Science. Merzenich is something of a living legend in neuroscience, a co-inventor of cochlear implants and one of the pioneers of the theory of neuroplasticity, which asserts that the brain continues to develop throughout a lifetime. Treating schizophrenia with brain training is based on the theory that the confusion and fear the disease creates may occur because the brain’s expectations about what will happen do not match up with what actually happens. That disconnect might be traced to a problem with verbal and auditory processing of information, something that brain training targets. © 1996-2013 The Washington Post
By Erin Wayman BOSTON — “Birdbrain” may not be much of an insult: Humans and songbirds share genetic changes affecting parts of the brain related to singing and speaking, new research shows. The finding may help scientists better understand how human language evolved, as well as unravel the causes of speech impairments. Neurobiologist Erich Jarvis of Duke University Medical Center in Durham, N.C., and colleagues discovered roughly 80 genes that turn on and off in similar ways in the brains of humans and songbirds such as zebra finches and parakeets. This gene activity, which occurs in brain regions involved in the ability to imitate sounds and to speak and sing, is not present in birds that can’t learn songs or mimic sounds. Jarvis described the work February 15 at the annual meeting of the American Association for the Advancement of Science. Songbirds are good models for language because the birds are born not knowing the songs they will sing as adults. Like human infants learning a specific language, the birds have to observe and imitate others to pick up the tunes they croon. The ancestors of humans and songbirds split some 300 million years ago, suggesting the two groups independently acquired a similar capacity for song. With the new results and other recent research, Jarvis said, “I feel more comfortable that we can link structures in songbird brains to analogous structures in human brains due to convergent evolution.” © Society for Science & the Public 2000 - 2013
Changing the channel on what TV children watch could improve their behaviour, but watching too much regular programming may have harmful long-term consequences, new research suggests. In Monday's issue of the journal Pediatrics, researchers reported that preschoolers spent less time watching violent programming when they were randomly assigned to participate in a program that encouraged aggression-filled shows to be replaced with educational or empathy-building viewing compared with a control group. Muppets Bert, left, and Ernie, from the children's program Sesame Street, were created to teach preschoolers that people can be good friends with those who are very different from themselves, which builds empathy. "We demonstrated that an intervention to modify the viewing habits of preschool-aged children can significantly enhance their overall social and emotional competence and that low-income boys may derive the greatest benefit," Dr. Dimitri Christakis of Seattle Children's Research Institute and his co-authors concluded. "Although television is frequently implicated as a cause of many problems in children, our research indicates that it may also be part of the solution." There was no difference in total viewing time between the 820 families involved in the study. The educational or "prosocial" programs included Sesame Street, Dora the Explorer and Super Why. A second category of shows also promoted co-operative problem-solving and non-violent conflict resolution but inconsistently, such as on Mickey Mouse Clubhouse. © CBC 2013